Method of treating containers for food



United States Patent METHOD OF TREATING CONTAINERS FOR FOOD Albert C.Edgar, River Forest, and Hiram T. Spannuth, Chicago, Ill., assiguors toWilson & .Co., Inc., a corporation of Delaware No Drawing. Originalapplication December 17, 1954, Serial No. 476,056, now Patent No.2,735,354, dated February 21, 1956. Divided and this applicationFebruary 7, 1956, Serial No. 5,63 ,8,46

19 Claims. (Cl. 99-187) This invention relates to methods for preventingthe adhesion of meat and other prote'inaceous meaty materials totheinner surfaces of containers therefor inwhich the said materials arecooked.

This application is a division of our application Serial No. 476,056,filed December 17, 1954, 'now Patent No. 2,735,354, granted February 21,1956.

In the manufacture of canned meats such as luncheon meats, corned beefhash, spiced ham, potted meats, salmon and like proteinaceous meatymaterials, the containers, usually metal cans, are filled with the meat,covered, and sealed. These cansare-generally made of metal, suitably ofsheet iron. Preferably they have been used with the interior surfacesthereof coated with tin and/or lacquer in accordance with standardprocedures. After the cans are filled :with the .meat'sproduct they :aresealed and the sealed :cans are ithentplaced in a steam retort orsimilar cooker, and cooked, frequently under pressure, for about one to,two hours, the amount of pressure and the time of cooking depending onthe kind of meat and the size of the can used.

A serious problem in the manufacture of canned meats has been thetendency of these products to adhere to the interior surfaces of thecans as a result of the cooking operation. This adhesion of meat to thecan not only causes difliculty in effecting a complete removal of thecontents of the can, but further results in wastage and inconvenience tothe consumer who has to scrape'ofi' the adhering meat from the sides andbottom of the container. Furthermore, the appearance of the-contents isfrenquently impaired, particularlywith-products such as luncheon meatswhich are to be removed from the can as a formed cohesiveunit,because:portions-of theadhering surface meat are torn away duringremoval of the meat from the can,leaving an unsightly fragmentedproduct,portions of which are lost to the consumer for "the purpose intended.

This tendency of the meat :to adhere to the interior surfaces of the canis encountered vwith .all of theusua'l containers, the interior metallicor other conventional surfaces of the container jhaving been treated orcoated with lacquer, tin and the like' in accordance with conventionalprocedures.

Th .can r le e age t to rth si venti n p event h adhesion ofproteinaceons ,meaty ,materials to the interior walls of the can inwhich the meaty materials are cooked. The compositions -,and compoundswhich may be used as can release agents in accordance with the inventionare, preferably, substantially .wvater-i-nsoluble, solid or semi-solidsyntheticzmaterials having-amelting point above about 155 R, which whendeposited tina film on a surface, particularly a metal surface, formsthereon an interface of wax-likecharacter which is preferentiallyadherent to the surface rather than to the contents of thecanattemperaturesabove ,about .15 ;F., and which is non-adherentto'proteinaceousmeaty materials.

The can release compositions and compoundsof the 2 V invention .are, forall practical purposes, inert, easy and economical to manufacture andwithstand, as coatings, the mechanical action of the hot and cold waterwashing treatments, the filling step and the processing opera; tions inthe packing plant.

In a preferred embodiment of the invention, the can release agents,which are inherently adapted to be ap-'' plied as a thin fused coatingor in solution in a volatile solvent on the container stock eitherbefore or after it has been formed into a container, are suspended ordis} solved in a conventional can coating lacquer or enamel, applied tothe container or container stock. Such lacquer or enamel may alreadyhave been ,used to prepare the container before packing and the canrelease agent ap plied thereover as a coating, by conventional coatingprocedures such as spraying, swabbing, dipping, fusion coating etc., butcompounds and mixtures of compounds having melting points below F., aspointed out below, when incorporated into the lacquer or enamel which isapplied ,as the usual coating, surprisingly fulfill the requirement thatthe can release agent adhere preferentially to the container surfacerather than to the 'proteinaceous material during and after the usualpacking operations so that effectively these lacquer compositionscontain no components which would adhere to the proteinaceous material.

The can release agents of the invention are not limited in theirapplication to proteinaceous meaty materials such as animal protein,since they can be readily applied with advantage to marine proteinmaterials (fish and fish products), to starchy materials which exhibitthe same tendency to adhere to the sides of the container and to manyother food products .which are cooked in a can preliminary to sale. Norare the can release agents of the invention limited to metal containersor cans since plastic sheet material, .plastic containers, glass, paperand similar wrapping materials may be coated or c overed toeffectivelyovercome the tendencyvof ,the protein food product to adhere to thecontainer or package, which tendency has been heretofore particularlynoted after loading the .llncooked or partially cooked food product intocontainers, sealing thecontainers and processing the containers underhigh temperature and pressure in the food processing plant even throughthe separately cooked food product may not cling to the wrapping.material in the absence of this processing operation in the container.

,The preferred compounds useful as can-release agents non-adherent toproteinaceous meaty materials are semisolidor solid cycloimidinesmelting above about 155 5., preferably above about 212 F., in which anacyl from a Cmto C28 acid, or a mixture of such fatty acids, is modifiedas .acylimino in .a cycloimidine structure, bridged :or ,unbridged, ofthe formula:

I in which cycloimidine structure the intramolecular reaction of theacyl carbonyi=C=O with a primary amino residue of the amine reactantforms a C to N double bond in a linkage which closes the cycloimidinering about the N-C residue of N-acyl.

The-bridging of cycloimidine rings takes place through reaction with alower aliphatic aldehyde (formaldehyde, butyraldehyde, glyoxal, ormixtures thereof).

.Forconvenience and to facilitate the understanding of thecompoundstructures of the can release agents in accordance with the invention,they are summarized'below, exemplified specifically, and their methodsof preparation are given, under the following group headings,

it being understood that any' one or mixtures may be used:

I. Alkylcycloimidine compounds II. bridged alkyl cycloimidine compoundsIII. Bis cyclo compounds IV. Aldehyde reaction products of group III.

GROUP I.ALKYL CYCLOIMIDINE COMPOUNDS I 1. Products containing thecycloimidine ring These compounds are closed ring compounds which arevariously referred to as glyoxalidines, imidazolines or cycloimidineshaving a basic ring structure as follows:

R- C iN-C H2 N- H:

wherein R is from a fatty acid of the C to C28 series, saturated orunsaturated.

In place of ethylenediamine other polyamines can be used. Examples are,propylenediamine, diethylenetriamine, triethylene tetramine,tetraethylenepentamine dipropylene triamine, etc. Propylenediamine givesthe same type structure as immediately above.

The saturated fatty acids give hard solids, the unsaturated fatty acidsgive stiff greases to resinous materials. They have high melting points.

2. Cycloimidine and bridged cycloimidine compounds The cycloimidinecompounds useful as can release agents are grouped as follows:

a. The reaction products of fatty acids C10 to Car; with an aliphaticdiamine at temperatures between about 120 and 300 C..to evolve in excessof 1.5 mols of water from the mixture, for each mol of fatty acid. Anexample of such a product is the reaction product of'l mol of stearicacid and 1 mol ethylenediamine having the formula:

which is a solid melting at about 280 F. Cooled rapidly in a thin filmit forms a continuous film, firm and hard, which is an excellent canrelease agent.

b. The reaction product of two mols of a above and 1 mol of an aldehydesuch as formaldehyde produces hard wax-like compounds with the splittingoff of additional water. Thus, as an example, such a compound is formedby reacting stearic acid with ethylenediamine as in a above, cooling tojust above the freezing point and adding paraformaldehyde, an additionalmolecule of water being split off. The proportions are two mols of aabove and one mol of formaldehyde. The formula of the product is:

Cl1H|lC=N -CHQ N H: (1112 /N(| Hz CnHasC=N-CH2 The product is a lightcolored, hard wax-like material, whose melting point is about 288 F.

c. The reaction products of fatty acids, C10 to C28, with a polyalkylenepolyamine, examples of which are diethylene triamine, triethylenetetramine, tetraethylene pentamine. A mixture of fatty acid and amine ina mol for mol ratio is heated from 120 C. to 300 C., to remove in excessof 1.5 mols of water per mol of fatty acid, and close the cycloimidinering.

An example of such a product is the reaction product of 1 mol of stearicacid and 1 mol of diethylenetriamine. Two cycloimidine ring formationsare observed, the first being through the 1,2 nitrogen, and the secondthrough the 1,3 nitrogen. When the reaction is carried out atatmospheric pressure in an open vessel, the cooled melt is nothomogeneous; two fractions appear which can be separated. One fractionis almost white, and crystalline, and melts at about 212 F. This appearsto be the 1,2

; closure:

' The second fraction is amorphous, off white, and melts at about 194 F.This appears to be the 1,3 closure:

C|1H;5O=NCH:

d. The reaction products of hydroxyalkylalkylene polyamines of the 1,2series and at least one member of the group consisting of normal fattyacids of the C10 to C25 series, amides of said acids, and esters of saidacids, at temperatures between about C. and about 300 C., water ofreaction being continuously removed from the reaction mixture during theheating, to effect the splitting out of water in excess of 1.5 mols foreach mol of free fatty acid, and in excess of 0.5 mol for each mol ofcombined fatty acid involved.

For example, 1 mol of stearic acid reacted with 1 mol of'hydroxyethylethylene diamine splits off two mols of water. The structural formula is'as follows:

wherein Rris alkyl containing from 9 to 28 carbon atoms; Rz is alkylene,amino substituted alkylene or oxy-substituted. alkylene; and R3 is loweralkyl or hydrogen.

GROUP 'II.BRIDGED 'ALKYL CYCLOIMIDINE COMPOUNDS The reaction products ofgroup I, 0 above, with aldehydes, such as formaldehyde, introduce analkylene linkage or bridge. Generally, the melting points of themethylene linked rings are usually very close or slightly higher thanthe melting point of the ring structure. The melting points of thealdehyde reaction products of c with either one or two mols offormaldehyde lie between the two fractions, ranging from about 201 F. to205 R, which indicates that a mixture of 1,2 rings and 1,3 rings isobtained. The melting point with 2 mols of formaldehyde being on thelower side. The four structural formulas are:

Axis Hzwherein 2 mols of the 1,2 ring are reacted with 1 mol offormaldehyde.

wherein 2 mols of the 1,2 ring are reacted with 2 mols of formaldehyde.

Axis

wherein 2 mols of the 1,3 ring are reacted with 2 mols of formaldehyde.

As the number of Nsin the polyamines are increased, the reactionproducts with the fatty acid become increasingly complex, and as wouldbe expected various mixtures are encountered. This is not only observedwith respect to the reaction of the fatty acid and the polyethyleneamine, "bu'halso with the further reactions with formaldehyde, whereinthe complexity :is still furtherram- The polyfunctional amine structureof triethylene itetramine:

is the basis for the complexity of the derivatives, through the stagesof soap, amide, and ring structure.

.In the case of a simple polyamine, ethylenediamine, it is 'not adifiicult'task to obtain the bis stearoyl ethylene diamine "orthe ringstructure by proper 'proportioning of the reactants.

However, as the complexity of :the .polyamine increases, the preparationis more difficult. In triethylenetetramine it can be observed thateither of two or more possibilities exist when 2 molsof fatty acid arereacted with 1 mol of the polyamine. By reacting stearic acid throughthe terminal nitrogen atoms the N,N bis-stearoyl triethylenetetramine isobtained. The ring structures are also produced throughthe-ring-closureflf .l,21-nitrogen and 3,4

nitrogen. in the first instance 1 mol of water is split off for each molof fatty acid, in the second instance 2 mols of water are split off foreach mol of fatty acid.

But when stearic acid is reacted, 2 mols 'of fatty acid with 1 mol ofethylenediamine, a stable condition exists after 1 mol of water isremoved for-each mol of fatty acid, and even prolonged heating atelevated temperatures, on the order of 200 C. results in little change;if anything, decomposition or oxidation sets in. Thus, N,Nbis-stearoylethylenediamine is so stable that ring closure is noteffected upon heating. However, when 2 mols :of

stearic acid are heated with 1 mol of triethylenetetra:

mine, as the temperature rises, one mol of water is evolved at 200 C.and more water is progressively lost as the temperature is increased. At200 C. the product is a light yellow colored wax-like material, meltingat about 230 F. As heating progresses, water is given off more slowly.

After a total of 1.5 mols of waterare lost the material is darker incolor, a little less bright and melts at about 203 F. to 212 PX, themelting point being less sharp. In contrast to this, continued heatingof the N,N' bisstearoylethylenediamine at moderate temperatures resultsin an increase in melting point, due to distillation of unsaturatedcomponents which may be present. The ring structure of stearic acid and,ethylenediamine generally has a lower melting point than thebis-stearoylethylenediamine. The decrease in melting point is due to theformation of the ring structure.

Larger molecules of wax-like character are obtained when these productsare further reacted with formaldeh-yde to introduce bridges of methylenelinkages. .Applicants do not wish to limit their process, therefore, tothe specific examples and instances set forth :in the foregoing, butrather include all of the complexes of wax-like nature and/or suitablemelting points for use as can release agents.

GROUP III.-BIS CYCLO COMPOUNDS These compositions are obtained byreacting normal fatty acids having 10 or more carbon atoms in the chain,with polyalkylene polyamines having at least four nitrogen atoms in thepolyamine, and wherein two mols of acid are reacted with one mol of thepolyalkylene polyamine at elevated temperatures on the order of .to 300C. until 3 to 4 mols of water are driven off. These products contain thegeneralstructure:

wherein R is a normal alkyl of at least 9 carbon atoms length. R1 is Hor lower alkyl.

n is a whole number greater than 1.

x may be zero or a whole number.

The properties can be radically altered by reacting mixed long and shortchain fatty acids with the desired amine, i. e. C1 to Ca fatty acids inadmixture with C10 to C28 fatty acids, the total mol proportion of acidto amine being constant, and preferably of widely disproportionatelengths, to wit: a C1 fatty acid and a C10 fatty acid, .or Cs andCra,orCz and C18, rather than-Csand C10 fatty acids, the mixtures having thegreater difference in lengths of carbon chains being preferred, andfurther mixtures in which the long chain fatty acids predominate arepreferred.

GROUP IV.ALDEHYDE REACTION PRODUCTS OF GROUP III Complex structuresobtained by the reaction of the bis-cycloimidine with aldehyde attemperatures from 150 to 300 C. which may be simple alkylol additionproducts, or complex derivatives of bis-cycloimidines and aldehydes ofindeterminate structure.

Examples of bis cycloimidines and their aldehyde reaction productsobtained by this procedure effective as can release agents, are:

1. Bis cycloimidine from stearic acid and tetraethylene pentamine,melting point 147149 F.

2 Reaction product of 1 mol of product 1 with 1 mol of formaldehyde,melting point 143-147 F.

3. Bis cycloimidine from stearic acid and triethylene tetramine, meltingpoint 205 207 F.

4. Reaction product of 1 mol of product 3 with 1 mol of formaldehyde,melting point 220 F.

The compounds, compositions and mixtures of the present inventionapplied as can release films to the container wall for preferentialadherence to the container surface rather than to the proteinaceouscontents of the can are effective for release of the proteinaceouscontents, when applied as a coating, in an amount of as little as 0.2milligram per square inch of container surfaces.

The amount of material which is applied to the containers may vary frombetween about 0.2 to 1.0 or more mgs. of material per sq. in. ofcontainer surface, depending upon the specific product used and the meatto be packaged. In general, amounts of material in excess of 1.0 mg. persq. in. tend to be wasteful of the material,- but such amounts may beused, if desired. Less than 0.1 mg. of material per sq. in. of containersurface will not ordinarily satisfactorily serve as a release agent.From 0.01 gm. to 0.10 gm. of material is usually satisfactory for thecoating of an ordinary 12 oz. food can, and a preferred amount for thispurpose is 0.02 to 0.05 gm.

When a can release agent product of the character described above isapplied as a film uniformly over the interior surfaces of the container,the proteinaceous meaty material packed in the container falls outreadily from the container when the same is inverted and there are nopatches of particles adhering to the surfaces of the container. In mostcases the meat falls out as an unbroken mass, thus presenting anappetizing and pleasing appearance. This was generally not the case withmeat removed from cans treated in accordance with prior art procedures.

The can release agents may be incorporated in the conventional lacqueror enamel coatings which may be used for coating of the can stock. Aneffective amount of the can release agent in the can coating lacquer isfrom about 4% to about 12% by weight of the lacquer. Larger amounts tendto be wasteful of the material. Smaller amounts than 4% may be effectivewith certain more efficient can release agents, in the same manner assmaller amounts are effective as fusion coatings, but more uniformresults are obtained at a minimum of about 4% (by weight) of agentrelative to lacquer.

Better results are generally obtained when the agent is merelysuspended, at room temperature, in a solvent dispersion of theconventional lacquer. However, the agent may be added at the end of thecooking and bodying operation during which the lacquer is prepared fromthe resin, oil and mineral spirits just before the lacquer is cooled. Alarger amount (7%18% by weight) of the agent may be added to the lacquerand heated -10 minutes at the lower cooking range 450550 F.Surprisingly, can release agents melting below 155 F. can beincorporated in the lacquer in these larger amounts to provide anenameled coating of good releasing properzgsboaid were coated with a hotbenzene solution-suspension of the agents. All the coated cans were thenheated in a C. oven for 20 minutes. It was necessary to heat can 17 overa hot plate in order to melt and fuse the agent. The coated cans werethen filled with chopped beef, sealed, and processed by the usual plantprocedure. for a period of 75 minutes at 230 F., and inspected.

All of the compounds tested exhibited good releasing qualities.

Results:

Grams Amount Coating Compound M.P., Can of wax ofAdhe- Bottom F. No.oncan sionon sides Stoaryl acetyl cycloirni- 284 25 .0209 None None.

dine of ethylenediamine (.25 mol stearic acid .75 mol acetic acid).Stearyl capryl cycloimi- 274282 2 .0176 do Slight.

dine of ethylene liamine (.0 mol stearic acid .1 mol capric acid).

0 274-282 33 .1277 .do. None. Mixed (Jr-C10 cycloimi- 304-306 26 .0309do Do.

dine (.1 mol acetic acid .9 mol capric acid). 02-01 cycloimidine (.5275-286 9 .0714 do Do.

mol acetic acid .5 mol stearic acid). Deeyl cycloimidine 311-315 17.0326 do.. Do. Bis-stearoyl cycloimi- 207214 8 .0520 -do. Do.

dine of triethylene tetramine tri-mathylenc. Stearoyl cycloimidine of173-221 22 .0460 do Do.

triethylene tetramine.

Example 1.-One mol of stearic acid, 280 parts by weight, was reactedwith one mol of diethylene triamine at 150-250 C. until 2 mols of waterwere driven off, to give a composition thought to be:

C. until 1 mol of water was removed to give a structure thought to be:

C11 s5-C=N-CH2 N- H: H O HrQHg-Ik-ii-CUHM having both acyl amide andalkyl cycloimidine structures. This product was reacted withformaldehyde in ratio of 2 mols to 1 of p-formaldehyde at 150-480 C., 1mol of water was driven off to give the bridged product:

These products are satisfactory can release agents.

An additional me], 280 parts, of stearic acid was added and the heatingcontinued until an additional 18 parts, 1 mol, of water waslost, to givetheiprodu'ct'thought-to be:

as in the preceding example. Two mols, 1104 parts, of this product werereacted with p-formalde'hyde, two mols, 60 parts, at -150-l80 C., until2 rnols, 36 parts of water were lost. The addition of morep-formaldehyderesulted in formaldehyde fumes and no gain in weight indicating thebridged structure: 7

These products are satisfactory .can .release agents.

Our invention is not to be construed as limited to the methods ofapplication described in the illustrative examples since other methodsmay be used, as will be evident to skilled workers in the art.

We claim:

1. The process of preventing the adhesion of food material to the innersurfaces of a container in which the food material is cooked, whichcomprises applying to such surfaces prior to cooking the said materialin said container, a coating comprising a cycloimidine compound havingtherein the group in which n is a whole number greater than 1 and R isan alkyl radical having at least 9 carbon atoms, said compound having amelting point above about 155 F., and cooking the said material in saidcontainer while the same is in contact with said coating.

2. The process of preventing the adhesion of food material to the innersurfaces of a container in which the food material is cooked, whichcomprises applying to such surfaces prior to cooking the said material:in said container, a coating comprising a waxy cycloimidine compoundhaving therein the group in which n is a whole number greater than 1 andR is an alkyl radical having at least 9 carbon atoms, said compoundhaving a melting point above about F., and cooking the said material insaid container while the same is in contact with said coating.

3. The process of preventing the adhesion of food material to the innersurfaces of a container in which the food material is cooked, whichcomprises applying to such surfaces prior to cooking the said materialin said container, a coating comprising a waxy cycloimidine compoundhaving therein the group in which n is a whole number greater than 1 andR is an alkyl radical derived from a C10 to C28 fatty acid, saidcompound having a melting point above about 155 F., and cooking the saidmaterial in saidcontainer while the same is in-contact with saidcoating.

4. The process of preventing the adhesion of food material to the innersurfaces of a container in which the food material is cooked, whichcomprises applying to such surfaces prior to cooking the said materialin said container, a coating comprising an alkylene diamine,alkylcycloimidine compound wherein the alkyl radical contains at least 9carbon atoms, and cooking the said material in said container while thesame is in contact with said coating.

5. The process of claim 4 wherein the cycloimidine compound isstearyl-acetyl cycloimidine of ethylene diamine.

6. The process of preventing the adhesion of food material to the innersurfaces of a container in which the food material is cooked, whichcomprises applying to such surfaces prior to cooking the said materialin said container, a coating comprising a .polyalkylene, polyamino,alkylcycloimidine compound wherein the alkyl radical contains at least.9 carbonatoms, and cooking the said material in said container wholethe same is in contact with said coating.

7. The process of claim 6 wherein the cycloimidine compound is thestearoyl'cycloimidine of triethylene tetramine.

8. The process of preventing the adhesion of food material to the innersurfaces of a container in which the food material is cooked, whichcomprises applying to such surfaces prior to cooking the said materialin said container, a coating comprising an alkylene,polyalkylcycloimidine compound wherein the alkyl radical contains atleast 9 carbon atoms, and cooking the said material in said containerwhile the same is in contact with said coating.

9. The process of claim 8 wherein the cycloimidine compound isbis-stearoylcycloimidine of triethylenetetraminetrimethylene.

10. The process of preventing the adhesion of food material to the innersurfaces of a container in which the food material is cooked, whichcomprises applying to such surfaces prior to cooking the said materialin said container, a coating comprising an acylated, alkylcycloimidinecompound, wherein the alkyl radical contains at least 9 carbon atoms,and cooking the said material in said container While the same is incontact with said coating.

11. The process of claim 10 wherein the cycloimidine compound isstearoylaminoethylene, stearylethylenediaminecycloimidine.

12. The process of preventing the adhesion of food material to the innersurfaces of a container in which the food material is cooked, whichcomprises applying to such surfaces prior to cooking the said materialin said container, a coating comprising an alkylene, polyacylatedalkylcycloimidine compound wherein the alkyl radical contains at least 9carbon atoms, and cooking the said material in said container while thesame is in contact with said coating.

13. The process of claim 12 wherein the cycloimidine compound isdimethylene, bis-stearoyldiaminodiethylenc, stearyl, ethylene diaminecycloimidine.

14. In the process of preventing the adhesion of food material to theinner surfaces of a container in which the food material is cooked, thestep comprising applying to such surfaces prior to cooking the saidmaterial in said container, a coating comprising a cycloimidine compoundhaving therein the group RC=*N((]1-) i in which n is a whole numbergreater than 1 and R is an alkyl radical having at least 9 carbon atoms,said compound having a melting point above about 155 F.

15. In the process of preventing the adhesion of food material to theinner surfaces of a container in which the food material is cooked, thestep comprising applying to such surfaces prior to cooking the saidmaterial in said container, a coating comprising a waxy cycloimidinecompound having therein the group IR-C=N-(( J),t I in which n is a wholenumber greater than 1 and R is an alkyl radical having at least 9 carbonatoms, said compound having a melting point above about 155 F.

16. In the process of preventing the adhesion of food material to theinner surfaces of a container in which the food material is cooked, thestep comprising applying to such surfaces prior to cooking the saidmaterial in said container, a coating comprising a waxy cycloimidinecompound having therein the group 7 t in which n is a whole numbergreater than 1 and R is an alkyl radical derived from a C10 to C28 fattyacid, said compound having a melting point above about F.

17. The process of preventing the adhesion of food material to the innersurfaces of a container in which the food material is cooked, whichcomprises applying to such surfaces prior to cooking the said materialin said container, a coating comprising a synthetic nitrogen-containingproduct derived from normal C10 to C28 fatty acids and amines selectedfrom the class consisting of alkylene diamines and polyalkylenepolyamines, said product having a melting point above about 155 F. andbeing characterized by containing both a normal acylamino residue and acycloimidine ring in the same molecule.

18. In the process of preventing the adhesion of food material to theinner surfaces of a container in which the food material is cooked, thestep comprising applying to such surfaces prior to cooking the saidmaterial in said container, a coating comprising stearyl cycloimidine ofethylene diamine.

19. The process of preventing the adhesion of food material to the innersurfaces of a container in which said food material is cooked, whichcomprises applying to such surfaces prior to cooking the said materialin said container, a coating comprising a nitrogen-containing productderived from C10 to C28 fatty acids and amines selected from the classconsisting of alkylene diamines and polyalkylene polyamines, saidproduct having a melting point above about 155 F. and beingcharacterized by a plurality of alkyl-cycloimidine rings in thestructure.

References Cited in the file of this patent UNITED STATES PATENTS2,098,538 Charch et al Nov. 9, 1937 2,124,823 Kronquest July 26, 19382,185,031 MacLaren et a1. Dec. 26, 1939 2,380,043 Hochwalt July 10, 19452,393,202 Stegemeyer Jan. 15, 1946 2,413,093 Warth et a1. Dec. 24, 19462,647,125 Gunderson July 28, 1953

1. THE PROCESS OF PREVENTING THE ADHESION OF FOOD MATERIAL TO THE INNERSURFACES OF A CONTAINER IN WHICH THE FOOD MATERIAL IS COOKED, WHICHCOMPRISES APPLYING TO SUCH SURFACES PRIOR TO COOKING THE SAID MATERIALIN SAID CONTAINER, A COATING CVOMPRISING A CYCLOIMIDINE COMPOUND HAVINGTHEREIN THE GROUP